Balakier Hanna, Sojecki Agata, Motamedi Gelareh, Librach Cifford
CReATe Program Inc. Sunnybrook and Women's College Health Sciences Center, University of Toronto, Toronto, Ontario, Canada.
Hum Reprod. 2004 Apr;19(4):982-7. doi: 10.1093/humrep/deh158. Epub 2004 Feb 12.
The purpose of this study was to investigate the fertilization rate and developmental potential of human oocytes in relation to the duration of their metaphase II (MII) arrest stage following the extrusion of the first polar body (1PB).
Immature metaphase I oocytes (MI; study oocytes, n = 468) that underwent meiotic maturation during brief in vitro culture and their matured in vivo, MII siblings (control oocytes, n = 3293) were subjected to ICSI. Fertilization and early cleavage were evaluated in both study and control groups.
The overall fertilization rate was significantly lower in the oocytes matured in vitro than in those matured in vivo (42 versus 77%, P < 0.0001). A significant relationship was observed between oocyte activation potential and the length of MII arrest. The majority of study oocytes injected soon after PB extrusion remained unfertilized (64%; 98/154 oocytes). The proportion of normally activated oocytes that contained two pronuclei and two PBs gradually increased with prolonged time of MII arrest (43 and 61% at 2 and 3-6 h after 1PB extrusion). Significantly more embryos originating from the study than control oocytes were arrested soon after the first two cleavage divisions (39 and 17%; P < 0.0001) and exhibited multinucleated blastomeres (23 and 13%; P < 0.0001), which suggests the existence of chromosomal abnormalities.
Human oocytes progressively develop the ability for full activation and normal development during the MII arrest stage.
本研究的目的是探讨人类卵母细胞在排出第一极体（1PB）后，其受精率和发育潜能与中期II（MII）停滞期持续时间的关系。
将在体外短暂培养期间经历减数分裂成熟的未成熟中期I卵母细胞（MI；研究卵母细胞，n = 468）及其体内成熟的MII同胞卵母细胞（对照卵母细胞，n = 3293）进行卵胞浆内单精子注射（ICSI）。对研究组和对照组的受精和早期卵裂情况进行评估。
体外成熟的卵母细胞的总体受精率显著低于体内成熟的卵母细胞（42%对77%，P < 0.0001）。观察到卵母细胞激活潜能与MII停滞时间之间存在显著关系。大多数在PB排出后不久注射的研究卵母细胞未受精（64%；98/154个卵母细胞）。随着MII停滞时间的延长，含有两个原核和两个PB的正常激活卵母细胞的比例逐渐增加（在1PB排出后2小时和3 - 6小时分别为43%和61%）。来自研究卵母细胞的胚胎比对照卵母细胞的胚胎在最初两次卵裂后不久停滞的比例显著更高（39%对17%；P < 0.0001），并且表现出多核卵裂球的比例也更高（23%对13%；P < 0.0001），这表明存在染色体异常。
人类卵母细胞在MII停滞期逐渐发展出完全激活和正常发育的能力。
